This invention relates to the field of sulfate-free personal care compositions such as body washes, shampoos, and hand soaps which include structured surfactants.
Structured surfactant compositions are pumpable compositions that exhibit shear-thinning viscosity and have the capacity physically to suspend water insoluble or partially water soluble ingredients. In many cases, the surfactant is present in such structured surfactant compositions in the form of packed spherulites, i.e., lamellar droplets, formed from an aqueous solution of the surfactant.
Structured surfactant compositions are useful in personal care applications, such as shampoos, body wash, hand soap, lotions, creams, conditioners, shaving products, facial washes, neutralizing shampoos, and skin treatments, in home care applications, such as liquid detergents, laundry detergents, hard surface cleansers, dish wash liquids, toilet bowl cleaners, car cleansers, and in other applications, such as oil field and agrochemical applications.
In some structured liquid compositions, relatively high levels of structurant are needed in order to create a structured system.
What is needed is a structured surfactant composition that provides typical structured surfactant properties, that is, shear-thinning viscosity and a capacity to suspend water insoluble or partially water soluble components, using a lower relative amount of structuring agent.
Conventional sulfate-free personal care compositions are comprised of water, surfactants, vegetable oils, fragrance, and other minor ingredients such as preservatives, additives, and pigments. Most such sulfate-free personal care compositions are limited to no more than 0.3% fragrance oil and/or vegetable oils which can be incorporated without affecting viscosity, foaming properties, moisturizing properties, deposition on target area. Upon increase of water insoluble compounds such as fragrance oils and vegetable oils with more than 0.5% affects stability, aesthetics and performance in terms of foam yield.
There is a strong interest in this art to provide personal care formulations which tolerate more vegetable oil. One approach to sulfate-free personal care formulations incorporates a surfactant chassis consisting of sodium lauroyl methyl isethionate, sodium lauroamphoacetate, sodium cocoyl isethionate, sodium methyl oleoyl taurate, and trisodium ethylenediamine disuccinate (Iselux SLB) available through Innospec, Inc. which is advertised as allowing up to 10% oils or other non-compatible actives.
It is an object of the present invention to address the ever increasing demand in the market for sulfate-free personal care formulations which tolerate more than 0.3 wt. % fragrance oil or vegetable oil without negatively affecting viscosity, foaming properties, moisturizing properties, deposition on target area, or stability.